Thermal Phase Fluctuations and Intrinsic Granularity in Cuprates
Abstract
The effect of thermal phase fluctuations on the ab-plane penetration depth, λ (T), of YBa_2Cu_3O_7-δ (YBCO) films from 4 to 40 unit cells thick is found to be much smaller than expected from the paradigm of cuprates as weakly-coupled 2D superconducting layers. No evidence is found for significant fluctuation effects at the hypothetical 2D transition temperature of a single CuO2 bilayer. The effective layer thickness that controls thermal phase fluctuations is found to be the thickness of the film, not the thickness of a copper oxide bilayer. This is consistent with the idea that cuprates are intrinsically granular in regards to electron transport, and that grains extend through the film thickness. Thus, thermal phase fluctuations are too weak to account for either the pseudogap or the rapid decrease of Tc with underdoping.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARL12012L